Throughout the film, Meeks walks the line between rebel and good student. He likes to joke, but he doesn't necessarily want to step out of line. He and Pitts make a radio, covertly (and use it to listen to rock'n'roll), but he also doesn't go too far out of his comfort zone at the DPS meetings.
Plus, he signs the petition against Mr. Keating like most of the rest of the boys. Meeks is just a little too meek (hey-o) to stand up against the group, even if he knows what they're doing is wrong.
But at the end of the day, "Meeks the meek" takes a back seat to "Meeks the DPS member." He summons the courage to stand up and salute Mr. Keating as his captain. Looks like he internalized some of the mentor's teachings…and the spirit of the DPS.
And that shows growth as a character.
We're betting he made another radio or two. Live on, rebel.